Buffer backing pad



Jan. 8, 1952 D. R. WILEY BUFFER BACKING PAD Filed Dec. 29, 1948 DA RFxELL HAW/L E Y FIE JH Patented Jan. 8, 1952 UNITED STATES I PATENT OFFICE 2,581,567 BUFFER BACKING PAD Darrell It. Wiley, Jackson, Mich. Application December 29, 1948, Serial No. 67,960

3 Claims.

The present invention relates to buffer backa lambs wool buffer, for the polishing of surl faces such as are found on automobile bodies, stoves, furniture and the like.

Heretofore it has been thought necessary that a buffer backing pad must be constructed of relatively inflexible material so that a certain pressure may be employed to drive a polishing compound into the painted surface to which it is being applied. These prior buffer backing pads have employed bodies of relatively hard rubber, at times cushioned with a small surface covering or relatively soft rubber. They have likewise been constructed of a semi-hard rubber molded over a stiffening agent such as a canvas disc, or like device.

A further objection to the prior manufacture of buffer backing pads constructed of a very soft rubber has been that it-was impossible to hold the soft rubber body on the metal insert under the pressures and speeds at which such devices operate.

This has been found especially true in those cases where the polishing must be done in relatively restricted places, such as at inside corners where both of the faces of the corner must be polished to an equal brilliance. Under such use a normally molded buffer backing pad, of relatively soft rubber, will tend to flex and to separate from the metal insert and run up over. the insert against the driving shaft. This continual flexing of the central portion of the backing pad tends to tear it up and wear it out long before any other part of the pad has worn out.

It is therefore an object of this invention to provide a buffer backing pad of molded soft rubber material.

A further object is to provide a buffer backing pad of soft rubber material molded on a metal insert and retained on said metal insert by mechanical means rather than by the use of binder materials or adhesives of any type.

A further object is to provide a buffer backing pad having the utmost in flexibility so that it may be used to polish in relatively small areas, the access to which is fairly restricted.

Still other objects and advantages in my buffer backing pad will be apparent from a considera tion of the following specification in connection with the appended claims and accompanying drawings, in which,

Fig. I is a plan view of a buffer backing pad constructed according to my invention,

Fig. II is a view in section along the line II--II of Fig. I, and

Fig. III is a broken view in section similar to Fig. II, with the backing pad bent as it would be while polishing in a corner, but, with the buffing pad omitted.

My buffer backing pad III, in the preferred form, one embodiment of which is shown, is molded on a central metal insert I2. The insert I2 may have a flat circular base I I, as shown, the base I I being preferably provided with a central well I6 positioned concentrically to the base I4. The upper side of the insert I2 is formed preferably With a substantially flat annular face I8, and joins the base [4 in a curved or rounded edge 20. A plurality of holes 22 communicate between the base I4 and the face II! for a purpose as will appear later.

The face I8 terminates, in the direction of the center of the insert I2, in a raised annular shoulder 24, concentric to the insert I2, and determining the lower face of an annular channel 26 which is topped by the boss 28. I have shown the annular channel 26 as having a rectangular cross-section, but I recognize that this crosssection could be of other shapes, such as triangular, and still function as it does.

The center of the insert I2 is, provided with a threaded aperture 30 extending from the boss 28 to the well IE and adapted to be connected to the end of driving shaft, not shown.

The soft rubber portion 32 of my buffer backing pad I0 is molded over the insert I2 in a cavity which will produce the shape shown in Figs. I and II. The lower face 34 is shaped to present an annular polishing face 36 which surrounds a concave surface 38 which in turn terminates in an annular shoulder 40 contiguous with the peripheral walls of the well I6. The well I6, the annular shoulder 40 and the frusto-conical concave surface 38 co-operate together to form a lower recess into which attachment structure may be inserted for holding a polishing disc, not shown, and the buffer backing pad III, on a drive shaft, not shown. If no suitable recess was provided it might be possible to get such metal articles as nuts, etc. in contact with the surface being polished.

The upper face 42 of the rubber portion 32 joins the lower polishing face 36 at the curved periphery 44 and forms a flat annular face to the junction with the central boss 28 at the upper edge of the annular channel 26. It will be noted that the face 42 is flat on its upper side, but that its lower side embraces the insert I2 and speciflcally the area around the annular shoulder The tapering cross-section of the soft rubber portion 32, adjacent the curved edge 44 gives a high degree of flexibility to the edge of my buffer backing pad. Likewise the thicknessof 2,581,567 f U {j '4 ment of the pad to an operating shaft, said actuating shaft an annular flange on said inflned therein, and a flexible pad part molded around said insert and extending below the base portion and into said annular channel, said flexible pad part having a free outer peripheral portion extending beyond said central insert and disposed normally substantially in the plane .of the latter.

.2. bufi r ackin pad co prising. .a central insert defining an aperture adapted to engage an actuating shaft, an annular flange on said insert and extending radially outwardly therefrom and defining a plurality of apertures extending the material immediately below the edge 20, as 1 compared with the thinner material overlying the surface 18, combine to furnish a relatively I solid central polishing-section and a flexible outer polishing section having suff cient support to allow the driving of the polish intoithe pores of the paint while flexing as: needed in restricted areas.

The annulus 46 by reason of its being shaped to mate exactly with the annular channel 25 resists any attempt to remove it therefrom. When the buffer backing pad 10 is used as shown in Fig. 111, the lower side of the soft rubber portion, as at 38,115 under tension, whereas the upper flat face 421s under compression, thereby tending to drive the annulus 46 further and more securely intoithe channel 25. The tension asat 38 tends to pull the pegs 48 more tightly into the holes 22' and likewise to seat theupper face 4.2.more firmly against the face N3 of the insert l2. 'Ihe compression of the upper face 42 likewise forces the face 42 into closer alliance with the face; l8 of the insert l2, and forces the annulus 46 into the channel 26. pressure on the face [8 adjacent the shoulder 24 being in a direction which is the resultant of an axial and a radially-inwards thrust, and with the pressure in the. channel26 being in a direc- Witfh the tion which is largely radially-inwards, it is insert having a base portion with a flat lower surface and a, frusto-conical upper surface and an upstanding boss projectingtherefrom, said insert 1. A buffer backing pad: comprising a central having a central aperture to permit'of the attachsubstantially parallel to the aperture through said flange in juxtaposition to the outer periphery thereof, said flange having a flat lower surface and a frusto-conical upper surface, said insert having an annular channel defined thereend axia ly spa ed from. ai lang a d a molded flexi l body port n' x n e ra ia 1y u w r ly f m s d. lan e nd r d l y i fd y to a d the t rea d ape ure and fil n said annularchannel and the apertures defined by said flange.

3. A buffer backing pad com rising a central insert having a central boss defining an annular channel and a tapered radial flange with a flat lower surface, a molded backing element surrounding said insert and extending into the channel on said boss, said element having'a relatively flat lower surface and a frusto-conical upper surface extending in unbroken line from the channel in said boss to the edge of said element. r I

' DARRELL, R; WILEY.

REFERENCES CITED The following references are of record in-the file of this patent:

' UNITED STATES PATENTS Number Name Date 1,778,470 Stratford Oct. 14, 1930 1,779,682 Stratford Oct. 28,1930 1,809,907 'NeWcomb June 16, 1931 21 32,917 Albertson Oct. 11, 193.8 2,172,407 Ramfi 1 Sept. 12, 193.9 2,281,722 Smith May 5,1942

. FOREIGN PATENTS Number Country 'Date France Q June 14, 1940 

